Add reusable use filtered queryset

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/user_management/querysets.py

@@ -0,0 +1,7 @@
+from __future__ import absolute_import, unicode_literals
+
+from django.contrib.auth import get_user_model
+
+
+def get_user_queryset():
+    return get_user_model().objects.filter(is_superuser=False, is_staff=False)